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browndj1642 · May 9, 2007, 03:40 PM

Hello, I turn my AC on for the first time this year. The compressor outside came on but the fan does not come on, in the furnace. I hear nothing going on in the furnace.
The heat works fine. The controller board was change over the winter.
Any ideas??

hvacservicetech_07 · May 9, 2007, 05:25 PM

The outdoor fan is not coming on? What model is the furnace? Will the indoor fan come on if you switch the t-stat to the ON position?

JackT · May 9, 2007, 05:28 PM

Call the contractor back to wire up the new board the correct way. They probably didn't connect the G terminals and the furnace blower is cycling with the fan temperature switch.

browndj1642 · May 9, 2007, 08:21 PM

Originally Posted by browndj1642

Hello, I turn my AC on for the first time this year. The compressor outside came on but the fan does not come on, in the furnace. I hear nothing going on in the furnace.
The heat works fine. The controller board was change over the winter.
Any ideas????

I should read my statements before I submit them. I was trying to say that I turned on my AC for the first time and the only thing that comes on is the compressor outside fan and all. The blower on the furnace does nothing. The blower works fine with the heat. There was no contractor, I replaced the controller board. I was troubleshooting over the phone with a HVAC person. I am an electrical engineer, but without a schematic I'm a little lost.
Rheem 90 Plus imperial about 15 years old.

Thanks for the fast response.

JackT · May 10, 2007, 02:50 AM

You need to see if you have 24 volts at your control board between the "G" & "C" ( transformer common ) terminal. 24 volts is needed to pull in your blower relay. If you don't have 24 volts, check your thermostat wiring and program. If you do have 24 volts, the blower relay may be bad. See if the blower will come on when you move the fan switch to the "ON" position. If it does, you may need to program the thermostat to bring on the blower in the cooling mode.

browndj1642 · May 10, 2007, 05:55 PM

Jack, I found part of the problem. Back during winter one of my limit switches went bad, of course I am not a contractor so I could not get the part. So I just bypassed it and it worked fine. So what I did was take the bypass off,(open) and the blower fan came on. But the compressor went off. Does this limit switch have to be in play for some odd reason, it is the high heat switch I believe.

hvacservicetech_07 · May 10, 2007, 08:45 PM

The limit switch will not effect the blower operation for cooling. Make sure that all of the fan wires are in the right position.

browndj1642 · May 10, 2007, 09:09 PM

Havacservicetech, the only problem with verifying the wiring is that I don't have a schematic. I don't suppose if I took a hi-res picture of my controller board, posted it on a website for all to see. Would someone be able to tell if I missed wired something?

hvacservicetech_07 · May 10, 2007, 09:19 PM

Actually that would help. What is the model of the furnace? Try to get a close up so that I can see the labeling on the control board.